Considerable information regarding the molecular diversity of human collagens is now available, and about 11 different molecular species are now thought to exist. Information regarding specific function for these many collagens is very incomplete, particularly for the "minor" collagens which form a small percentage of total tissue collagen. There is compositional and enzymatic evidence that these "minor" collagens form a noval class of collagens with presumably distinct specialized functions. There is no information about alterations of these materials in human health or disease. This project proposes to construct monoclonal antibodies (MCA) to the various human collagens with particular emphasis on the "minor" collagens, and use these reagent-grade MCA to microlocalize these collagens within tissues at the light and EM level to develop information regarding possible function(s). A specific hypothesis regarding the minor collagens will be tested, namely, that these materials are found only in the extracellular space at the cell membrane and serve as "exocytoskeletons" for the cells. We will also test the postulate that the Marfan syndrome is due to defects of Type V collagen observable by alterations in distribution and/or amount of this collagen in proximal aorta. We will also test the postulate that osteoarthritis (OA) is associated with the accumulation of the 1Alpha and 2Beta collagens in degenerated areas of OA articular cartilage. We anticipate that the proposed studies will provide specific information regarding the minor collagens and their possible role in Marfan syndrome and OA. In addition, acquisition of a library of MCA to various human collagens will facilitate multiple other studies of connective tissue in health and disease.